BEIJING — Rainstorms that are said to be the worst in five decades have flooded large areas of southwest China, washing out bridges, setting off a landslide that buried dozens of people and destroying a memorial to victims of the 2008 earthquake in Sichuan Province that flattened large parts of the same area.

The state news media reported Wednesday that heavy rains, which began last weekend, have killed more than 50 people across China and disrupted two million lives.

The worst flooding, in mountainous areas of Sichuan that include some of China’s most spectacular scenery, highlights the challenges of encouraging construction in places that are prone to heavy downpours and seismic activity. Some experts, citing frequent earthquakes and soil erosion caused by deforestation, have argued against the continued development of towns and cities along the Min, Fu and Jian Rivers, which snake through the steep canyons of the region.

The worst damage appeared to be in the city of Dujiangyan, where a rain-soaked mountainside gave way on Wednesday, burying 11 homes and as many as 40 people. Xinhua, the state news agency, said rescue workers and sniffer dogs from Chengdu, the provincial capital, were rushing to the area, which only recently recovered from the 2008 earthquake. The earthquake left 87,000 dead or missing.

Photo

Firefighters used a rope to help a woman walk across flood waters on Tuesday after heavy rains hit China's Sichuan Province.Credit
China Daily, via Reuters

Flooding submerged Qushan, the former county seat of Beichuan, once a city of 20,000 that was destroyed by the earthquake. The state news media said 23 feet of water had inundated a recently opened museum commemorating earthquake victims. Survivors have long since been moved to a new town center, and officials set aside about 10 square miles as a memorial.

The Oriental Morning Post, a newspaper based in Shanghai, urged the government to better protect the memorial area, which contains the remains of hundreds of people whose bodies were never recovered from the rubble.

“If we don’t take effective measures,” the editorial said, “in another 10 or 20 years the ruins might not be there at all.”

To the north, in Shanxi Province, 12 workers were killed Tuesday night when a violent rainstorm caused the collapse of an unfinished coal mine workshop they were building, People’s Daily reported, citing a statement from the city government of Jinzhong, where the accident occurred.

Mia Li contributed research.

A version of this article appears in print on July 11, 2013, on Page A4 of the New York edition with the headline: Rainstorms Flood Sichuan Province in China. Order Reprints|Today's Paper|Subscribe